Effect of an intraoral appliance on tongue pressure measured by force exerted during swallowing

Introduction: The goal of this study was to modify the transpalatal arch design that is used for vertical control of the molars, based on individual muscle strength and morphology features of the tongue during swallowing. Methods: Individual Silastic (Muller-Omicron, Cologne, Germany) swallowing tongue records were created and measured for 32 healthy volunteers. The transpalatal arches were modified by adding acrylic pads, based on the swallowing tongue records. Tongue pressure exerted on the hard palate and the acrylic pads at 3 distances to the palatal mucosa during swallowing was measured by pressure sensors for 18 subjects. Results: The intraclass correlation coefficient of the thickness of swallowing tongue records taken by 2 researchers was 0.977, indicating good consistency between these researchers. A significant negative correlation was found between the thickness of the swallowing tongue records and individual tongue pressure (r = -0.511; P<0.01). Tongue pressure exerted on the fabricated pads consistent with swallowing tongue records was significantly higher than on the hard palate, yet not significantly higher than tongue pressure exerted on the pads positioned 3 mm closer to the palatal mucosa. In contrast, increasing the distance of the pad 3 mm away from the mucosa led to significant augmentation of tongue pressure. Conclusions: Creating patient swallowing tongue records is a repeatable and reliable method to reflect individual differences in morphologic features and muscle strengths of the tongue. Decreasing the distance of the pads to the mucosa is preferable if a high force to intrude molars will not be used. On the premise of a patient's tolerance, increasing the distance of the pads away from the mucosa leads to augmentation of tongue force.